Process cartridges which are detachably mounted in copying apparatus are well known in the art. Some such cartridges are disclosed in U.S. Pat. Nos. 4,588,280; 4,591,258; 4,575,221; and 4,566,777. These cartridges typically include a photosensitive drum rotatably mounted in the cartridge housing, and generally a more or less clearance is provided between the housing or casing in order to allow smooth rotation of the photosensitive drum in the process cartridge housing. Such clearance generally results in a small longitudinal shift of the drum when the photosensitive drum is driven. One manner in which the sideways thrust is created is disclosed in U.S. Pat. No. 4,829,335, wherein longitudinal movement is created by the helical gear, and the cartridge continues to move against the main frame of the image- forming apparatus even after the initial engagement between the cartridge and the main frame. To provide the structure to permit this limited longitudinal movement, the cartridge in U.S. Pat. No. 4,829,335 is provided with a photosensitive drum having a helical gear formed on the annulus of an end member having a central opening therein to receive a shaft which is fixed to and extends from the main assembly of the copying appartaus and into the drum. The end member of the drum and the helical gear is made integral with each other and with the end of the photosensitive drum, and the drum rotates freely on the shaft.
It is, therefore, an object of the present invention to provide a process kit for use in an image-forming apparatus wherein the photosensitive drum in the process cartridge is provided with a gear for rotation thereof, the gear and the photosensitive drum cooperating in such a manner which will prevent frictional contact between the end of the photosensitive drum and the process cartridge housing and the cartridge housing and the main frame of the image-forming apparatus.